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Side effects

Burping and "sulphur burps" on a GLP-1

Of all the side effects people joke about, the eggy burp is the one they mention most. The labels call it eructation, and it is genuinely more common on these medicines than on placebo. The smell is unpleasant but usually harmless; what matters is what comes with it.

By the Cafeity teamUpdated 5 min read

The short answer

Burping (eructation) is a listed side effect of GLP-1 medicines: 7% of people on semaglutide 2.4 mg reported it against under 1% on placebo, 4–5% on tirzepatide against 1%, 4.5% on liraglutide 3 mg against 0.2%, and 6–8% on orforglipron against 1%.1234 "Sulphur" burps smell of rotten eggs because of gas produced as food is broken down; a slower-emptying stomach gives that more time. Smaller meals and going easy on fatty food are the main suggestions. Burping with severe stomach pain, persistent vomiting or diarrhoea needs a clinician.

Bar chart of burping (eructation) in the weight-management trials: semaglutide 2.4 mg 7% versus under 1% on placebo; tirzepatide up to 5% versus 1%; liraglutide 3 mg 4.5% versus 0.2%; orforglipron up to 8% versus 1%.
Share of trial participants who reported burping, from each medicine's US prescribing information. The labels do not distinguish sulphur-smelling burps from others. Not a head-to-head comparison.

How common burping is

The labels list burping — "eructation" — among the common reactions for each weight-management GLP-1. It is less common than nausea or constipation, but it stands out because it is so rarely reported on placebo.

Eructation (burping) in placebo-controlled weight-management trials, from the current US prescribing information.
MedicinePlaceboMedicine
Semaglutide 2.4 mg weekly injectionunder 1%7%
Tirzepatide weekly injection1%4% (5 mg), 5% (10 mg), 5% (15 mg)
Liraglutide 3 mg daily injection0.2%4.5%
Orforglipron daily tablet1%6% (5.5 mg), 8% (9 mg), 8% (17.2 mg)

Burping usually arrives in company. On the same labels, indigestion, reflux, bloating and wind are all more common than on placebo — for semaglutide 2.4 mg, indigestion 9% against 3% and bloating 7% against 5%.1 The semaglutide label also lists hiccups among the gastrointestinal reactions seen more often on treatment.1

Why they can smell of sulphur

The labels record burping, not what it smells like, so the explanation comes from how digestion works rather than from the trials. The rotten-egg smell is hydrogen sulphide, a gas produced as sulphur-containing foods are broken down in the gut. GLP-1 medicines slow the rate the stomach empties, which is part of how they work.12 Food that sits for longer has longer to produce gas, and some of it comes back up.

That also explains why some meals seem to trigger it more than others. Rich, fatty meals empty more slowly still. Large portions sit longer. And some foods — eggs, meat, some vegetables in the cabbage family — contain more sulphur to begin with. People differ a lot in which foods set them off, which is why a food-and-symptom log is more useful than any list.

What the eating guidance suggests

There is no trial of remedies for sulphur burps specifically. The broader guidance on gastrointestinal side effects of these medicines — the 2025 joint nutrition advisory — points in a consistent direction:5

  • Smaller, more frequent meals, so less sits in the stomach at once.
  • Going easy on fatty and fried food, which slows emptying further.
  • Eating slowly and stopping at the first sign of fullness.
  • Limiting alcohol, which the advisory notes may worsen nausea and reflux.

Beyond that, many people find carbonated drinks make burping worse, and that noticing their own trigger foods helps more than cutting out whole food groups. Protein matters too much on these medicines to drop eggs or meat on a hunch — log it first, then decide. Over-the-counter remedies are a question for a pharmacist, who can check them against your other medicines.

When burping comes with other symptoms

Sulphur burps on their own are unpleasant rather than dangerous. They matter more when they arrive with diarrhoea or vomiting, because the combination can lead to dehydration — and the labels warn that dehydration from gastrointestinal side effects has caused kidney problems.12 Severe stomach pain alongside any of it is a different matter altogether, and a reason to seek help.

If burping and reflux are the main problem, see heartburn, reflux and indigestion; if it is mostly bloating and wind, see bloating and gas.

When to contact your prescriber

Keeping a record of it

Burps are easiest to understand next to what you ate. Cafeity logs meals — by photo, search or barcode — on the same timeline as symptoms and doses, so after a week or two you can see whether yours follow particular foods, big meals, or the days after an injection.

Cafeity calories and macros screen: 284 of 2,550 kcal, protein 71 of 170 g, carbohydrate and fat, with steps and a how-you-feel mood check-in below.
Meals and macros for the day.
Cafeity "Your week, understood" screen: Ora explains that everything is calculated from your own log, offers questions such as "When are my symptoms worst?", and shows the week's protein, energy, water, weight trend, symptom days and a note that protein was 80 g under target.
Ask Ora which days your symptoms were worst.

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Common questions

Why do I get sulphur burps on a GLP-1?
The medicines slow stomach emptying, so food sits longer and has more time to produce gas, including hydrogen sulphide, which smells of rotten eggs.1 Burping itself is a listed side effect on every weight-management GLP-1 label.
Do sulphur burps go away?
Gastrointestinal reactions on these medicines are described as most common during dose escalation and decreasing over time.24 If burping persists, smaller meals and less fatty food are the usual first steps; a pharmacist or your prescriber can advise beyond that.
Which foods cause sulphur burps?
It varies from person to person. Rich, fatty and large meals are common culprits because they slow emptying further, and some foods naturally contain more sulphur. A food and symptom log is the most reliable way to find your own triggers.
Are sulphur burps a sign of something serious?
On their own, usually not. With severe stomach pain, persistent vomiting or diarrhoea, or yellowing of the skin or eyes, they are a reason to contact a clinician promptly.2

Sources

  1. Semaglutide injection and tablets for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 30 June 2026
  2. Tirzepatide injection for weight management and obstructive sleep apnoea — US prescribing information DailyMed, US National Library of Medicine, version published 2 September 2026
  3. Liraglutide 3 mg injection for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 15 June 2026
  4. Orforglipron tablets for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 13 August 2026
  5. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society Mozaffarian D et al. 2025 (published in four journals)

Written by the Cafeity team from the sources listed here. Figures from prescribing information are quoted as the label states them; trial results are averages from those trials, not predictions for any one person. This page has not yet been reviewed by a clinician — see the editorial policy for how pages are researched and corrected.